The answer is blowing in the wind: The warming went into the deep end

There has been an unusual surge of interest in the climate sensitivity based on the last decade’s worth of temperature measurements, and a lengthy story in the Economist tries to argue that the climate sensitivity may be lower than previously estimated. I think its conclusion is somewhat misguided because it missed some important pieces of information (also see skepticalscience’s take on this story here).

While the Economist referred to some unpublished work, it missed a new paper by Balmaseda et al. (2013) which provides a more in-depth insight. Balmaseda et al suggest that the recent years may not have much effect on the climate sensitivity after all, and according to their analysis, it is the winds blowing over the oceans that may be responsible for the ‘slow-down’ presented in the Economist.

An intensification of the trades has affected surface ocean currents called the subtropical gyres, and these changes have resulted in a predominance of the La Nina state. The La Nina phase is associated with a lower global mean temperature than usual.

Balmaseda et al’s results also suggested that a negative phase of the pacific decadal oscillation (PDO) may have made an imprint on the most recent years. In addition, they found that the deep ocean has warmed over the recent years, while the upper 300m of the oceans have ‘stabilised’.

The oceans can be compared to a battery that needs to be recharged after going flat. After the powerful 1997-98 El Nino, heat flowed out of the tropical oceans in order to heat the atmosphere (evaporative cooling) and the higher latitudes. The warming resumed after the ‘deflation’, but something happened after 1998: since then, the warming has involved the deep ocean to a much greater extent. A weakening of the Atlantic meridional overturning circulation (MOC) may have played a role in the deep ocean warming.

The recent changes in these decade-scale variations appear to have masked the real accumulation of heat on Earth.

The new knowledge from this paper, the way I read it, is the revelation of the role of winds for vertical mixing/diffusion of heat in a new analysis of the world oceans. Their results were derived through a set of different experiments testing the sensitivity to various assumptions and choices made for data inclusion and the ocean model assimilation set-up.

By running a set of different experiments with the ocean model, including different conditions, such as surface winds and different types of data, they explored which influence the different conditions have on their final conclusion.

The finding that the winds play a role for the state of the warming may not be surprising to oceanographers, although it may not necessarily be the first thing a meteorologist may consider.

206 Responses to “The answer is blowing in the wind: The warming went into the deep end”

“If more of the heat from global warming is going into the ocean, does that reduce the amount of surface warming (both transiently and long-term) that we should expect from doubling CO2?”

I interpret the land temperatures to provide an earlier foreshadowing of the eventual long-term surface warming, while the sea-surface temperatures to be a transitional temperature. This means that the global temperature has proportions of the SST and land temperature in its computation. Moreover, from the ratio of SST and land, we can estimate roughly how much heat is being sunk by the ocean depths.

I think it is interesting how well the numbers compose for the Hadley/CRU data sets. This essentially agrees with the current interpretation that approximately 1/2 of the excess heat is being absorbed by the ocean depths.

How does weakening of the Atlantic meridional overturning circulation contributes to the increase in the rate of deep ocean warming? If one conceives of the AMOC as a king of large scale current that works *against* convection, then it may look like weakening it would indeed have an effect similar to that of increasing convection. Is that how one can think of it? But if the AMOC itself is driven by the sinking of cold water in high latitudes, then it seems to be a form of convection. So, I have a hard time to picture how it may work towards increasing the rate of deep ocean warming. The case of PDO/ENSO is much more intuitive.

Pierre-Normand – you’re assuming that the AMOC will weaken. That’s pretty “old school” thinking, and contradicted by a lot of paleoclimate data.

Invigoration of the Antarctic Circumpolar Current by intensified westerlies, and a southward shift of the strongest westerlies so that they align with the ACC should lead to increased ventilation of the ocean interior.

Rob Painting, I’m not assuming this. I’m reacting to the comment in the original post regarding Balmaseda et al. (2013) “A weakening of the Atlantic meridional overturning circulation (MOC) may have played a role in the deep ocean warming.”

That’s what I was trying to understand. It’s a question about the recent past. I’m just trying to figure out how the weakening of the AMOC could have contributed to an increase in deep ocean heat content, as they suggest it might have. I can’t picture it so I’m seeking enlightenment.

Hank – the idea that the AMOC may undergo long-term slowdown is old school. The AMOC appears to have slowed, and may do so further in the near-future – as the polar oceans warm and land-based ice ends up in the ocean, thereby raising the buoyancy of surface waters. But the invigoration of the thermohaline circulation via the Southern Ocean, and the build up of heat at lower latitudes, may get it moving again. That would be more in line with physical considerations, and paleoclimate data from past warm periods.

One ocean heat source I haven’t noticed much, is the amount of heat contributed by undersea sources such as volcanoes, and other assorted heat pipes.

[Response: You haven’t noticed it much because it actually doesn’t matter much. I’ve said it before but I’ll say it again: averaged over the earth’s surface (or ocean bottom, geothermal heat is milliwatts; heat from the sun is hundreds of watts. Unless you are sitting right on top of the volcanoe, it does not matter. –eric]

As a lay reader I hesitate to comment, but Paul S in comment number 1 refers to a a SLR puzzle that I too have been wondering about. The recent estimates for increased glacier melt do not seem to fit with the near constant SLR (satellite data) trend unless the thermosteric contribution to expansion has reduced. As I understand it this would fit with more of the heat passing down into colder waters where the expansion for a given quantity of heat would be less. The 2010/2011 6mm fall in SLR was predicted by Nasa science to be the result of strong La Nina excessive rains captured on land by the Queensland floods and NE South America. This seems to have been confirmed by the subsequent end 2011/2012 return of sea level to the trend line. But interestingly SLR continued rising during 2012 and now into 2013 as shown by http://climate.nasa.gov/key_indicators/. Assuming there is no problem with the satellite measurement, could this be an indication that the combined steric and glacial melt contributions are now responding more strongly to the heat that is already in the Earth system ? If so this might also suggest that climate sensitivity is not less than previous concensus estimates. My apologies if I am misunderstanding something fundamental. It will be interesting to sea what SLR does next.

I take the point that with the satellite data record limited to the last twenty years, an exponential rise could be hidden behind the apparent linear trend.

I floated the idea that the current uptick in the rate of sea level rise during 2012/2013 (ENSO neutral conditions) might indicate that a stronger sea level response to global warming may now be taking place. Accepting that it might turn out to be just normal variation and data error combining to give a temporarily misleading record,I was wondering what other explanations readers might suggest.

I forgot to thank you for responding to my amateur post. I deeply admire the time and effort that busy scientists put into realclimate.org. It is a truly excellent web resource for giving to a global public audience, the evidence based resources for understanding climate science, accessing data, and honest discussion of conflicting ideas.

Cowards! You can’t even answer a few simple questions to unearth the truth! You refused to publish my post. You can’t handle even the simplest opposing view. Shows what your “science” is worth. Enjoy your crumbling religion ;)

“In addition, they found that the deep ocean has warmed over the recent years, while the upper 300m of the oceans have ‘stabilised’.”

That’s just silly. ARGO can’t find it. You seem to suggest that hot water doesn’t rise. There’s even a comment here from someone stating “heat is not temperature”. WHAT?!

Notably your “chart” above doesn’t show any acceleration whatsoever and, there’s no Y-scale. Are you measuring this in phlogistons?

Sea levels have been rising for tens of thousands of years, since the last deep ice age ended. There’s no acceleration evident today. Have you taken land subsidence into account? Have you even noticed charts of where it’s slowed?

How did the Australian Aborigine cross the oceans to get here? Maybe you should see this:

You seem utterly convinced that man-made CO2 (still a tiny trace gas in our atmosphere at 0.0397%) is going to burn the planet to hell tomorrow. Of course, when it comes to doomsayers, it’s always tomorrow, next week or in the future. That just continues until the next fearmongering “fad” comes along to be likewise always “predicted” in the future. Some questions for you:

Every exhalation is around 4% CO2 (40,000ppm – atmospere now 397ppm). How is it you don’t burn your tongue in the sun when you exhale that ENORMOUS 4% of CO2?

How is it that delicate aragonite corals evolved when CO2 was some 20x higher than today?

With CO2 so much higher in the past and you expecting a LINEAR scale to CO2 heat trapping effect, why was there never a runaway greenhouse, ever?

How is it that CO2 was many times higher than today even during deep ice ages?

You understand that CO2 is necessary for photosynthesis and farmers actually pump CO2 into their greenhouses to increase yields, right?

Do you know that Viking graves in Greenland now are in permafrost – something you can’t dig without hydraulics? Vikings colonised and farmed Greenland 1000 years ago, why did they leave 300 years later?

The Little Ice Age is documented in paintings from the 1600’s where the Thames and Hudson rivers froze 10ft thick and the locals held fairs on them. Are you aware of this at all? Are you aware this was caused by the “Maunder Minimum”, a time when very few Sunspots and Solar activity occurred?

Do you remember when an imminent “ice age” was predicted in the 70’s?

Are you aware that Global temps rose sharply between 1910 and 1940, then fell sharply between the 40’s to the 70’s? Did Man have something to do with it or is my next question the answer?

Do you understand the cycles of the oceans (PDO, AMO, ENSO) and their impact from warm to cool and back again over regular decadal scales?

Why is it that in a desert, you can fry during the day and freeze at night, but not in the tropics? What magical atmospheric component is missing in a desert to cause this and therefore, is CO2 actually trapping any catastrophic heat at all? A clue – notice how the night is usually warmer when it’s overcast?

Have you noticed that CO2 continues to climb but Global temps have flatlined for the last 17 YEARS? Why the disconnect?

Are you aware that according to well understood physical parameters, the effectiveness of CO2 as a greenhouse gas diminishes logarithmically with increasing concentration and from the current level of ~397 ppm, accordingly only ~5% of the effectiveness of CO2 as a greenhouse gas remains beyond the current level?

Do you understand that warm water outgasses CO2 – try opening a warm and a cold bottle of soda water. Do you now understand that the oceans could never become “acidic”, considering their pH ranges from 7.9 to 8.3, depending on where you measure it and, that the pH scale is also logarithmic?

How do you explain the findings of ancient tools and tree stumps under retreating glaciers?

Have you seen the geologic records that show CO2 rising AFTER temp rises by some hundreds of years?

Have you discovered Milankovitch Cycles – how the Earth has cyclical wobbles in its orbit being tugged on by other planets causing major changes in our distance from the Sun?

Have you discovered that on very regular cycles, the Earth suffers a major ice age about every 100,000 years lasting many times longer than our current interglacial? Do you think that’s connected to my previous question?

Why is it that some 90%+ of species live around the Equator?

Figures are readily available to show winters kill more people than summers – have you looked into them and why do you think retirees look forward to living in warmer climates?

Are you aware that the Arctic ice extent is now the same as the 1979 annual mean? Do you really think it’s going to be “ice free” at all this NH summer?

Are you also aware that cat 3+ cyclones making landfall in the US and tornadoes are at record lows? The NOAA has figures on that if you dare look.

Does it make sense that “climate scientists”, being largely (if not totally) government funded, need to continue blaming Man for CO2 ills since governments want to tax us on it and, if they say it’s not, they’ll lose their job?

Frankly, all of the tip-toeing, cherry-picking and completely unscientific (if not impossible) explanations I see on this site in support of AGW are truly far-fetched wonders of the age. You seem to suggest that surface winds are somehow stopping hot water from rising? Nonsense. All that rubbish and referencing to desperately try and explain-away the now 17 year warming pause.

If you get all the charts and scale them by whole degrees (something we might physically feel – maybe) then they’d be a straight line not even resembling static.

People, have a good look around and you’ll find there are more questions that require answering before spouting for certain that Man is to blame for climate change. It’s been doing it for billions of years and will continue to do so. There’s NO peer-reviewed study out there that can scientifically and unequivocally state that they can filter out Man’s warming signal from the natural noise.

If you keep believing point-blank the government and the lamestream media, you’ll look like a fool (you’re rapidly getting there) and have a lighter wallet to boot. Don’t be a puppet or a parrot to them. Remember this:

“When a well-packaged web of lies has been sold gradually to the masses over generations, the truth will seem utterly preposterous and its speaker a raving lunatic”.

If you refuse to publish this post or delete it, the volumes about your “science” will have been spoken.

[normally this would go to the borehole. We’re going to allow this one through for amusement however. -moderator]

The reason that your previous post is published in the Bore Hole is that every statement you make is either outright wrong or irrelevant while accurate information is readily available. Try the Start Here section on this site or the even more digestible form at SkepticalScience- http://www.skepticalscience.com/

Olaf, you are being laughed at which is rather sad because you obviously believe everything that you wrote. However, it shows that you have let yourself be misled by misinformation. On the other hand, suggesting to practicing scientists that they have missed something obvious because you have misunderstood the facts is frankly an act of appalling arrogance. If you prefer misinformation, then noone can help you. If you care about truth, pick the “fact” that you think is most telling and compare it to what the science really says (not what some unqualified blogger tells you it says). Then move to next “fact”. Do it one at a time. SkepticalScience.com is a good place to start with references to the science. READ the science. Some misinformation sites also reference papers but tell you it says the opposite to what it actually says, safe in the knowledge that deniers wont bother to check. This will tell you which sources to trust.

Mr. Koenders: How did you find out ? You are too clever for us. We always thought the Industrial Revolution was a bad idea, and for centuries we have been faking data, muzzling deniers, conspiring with green ecofascists to return human society to hunter gatherer lifestyles governed by our secret cabal of purple shamanistic druids. Even bicycles, wheelbarrows and arithmetic were to be outlawed in our sustainable, glorious vegan communes. But, alas, we are undone! Run to the hills! Flee to the valleys! Mr. Koenders has found us out. Our fiendish plans will come to naught! Woe is us !

Well Olaf, that’s quite an amped up little Gish gallop you’ve got there. I Googled around for a little background on your take on things and didn’t much care for the crusty hole I seemed to be headed down, so I backed out.

Apropos of nothing in particular, and after some random musing, this thought occurred to me–just putting it out there as a sort of general PSA: Guns and amphetamines don’t mix.

Just a comment on sensitivity (since it’s in the news these days – NYT anyway – and it’s relevant to this post):

Usually this is described as the sensitivity (variously defined in terms of time scales of course) due to doubling of CO2. However, nobody ever seems to mention: doubling from *what*? Offhand, I would not expect doubling from 400ppm to give the same delta T as doubling from, say, 250ppm.

Best answer I can find (wikipedia article on climate sensitivity, referring to IPCC 4th report) is that doubling corresponds to 540ppm, which would mean the baseline standard is 270ppm CO2.

Is that a universally agreed-upon standard for these kinds of studies? That is, does “doubling” universally mean going from 270ppm -> 540ppm?

Obviously we want apples-to-apples comparisons here, so it seems important to me that somebody make this clear. Apologies if this was in the original post. Regardless, whenever I see news articles on doubling (including posts here, if I am not mistaken), this information is often lacking.

Peter,
As the dependence is logarithmic in CO2 concentration, it doesn’t matter what your baseline is–double the concentration and you’ll get roughly an additional 2.8 degrees of warming. Normally, they are talking warming over pre-industrial levels, so roughly 270-280 ppmv.

This is a good question, and there’s two parts involved in answering it. The first question is what the radiative forcing is for successive CO2 doublings (essentially how effectively does each doubling of CO2 reduce the rate of radiation loss to space)? The the second question is how differently feedbacks may behave as a function of the initial climate state?

For the first part, there’s not much uncertainty; it doesn’t matter too much where you start from, at least over reasonable range of CO2 concentrations that is relevant for Earth. That’s because CO2 reduces the rate of radiation loss to space in roughly equal increments for successive CO2 doublings. That is, if the mean outgoing longwave radiation is OLR(0) then the OLR after each CO2 doubling can be roughly fit by the function OLR=OLR(0)-a*log(2). The coefficient “a” is approximately 4 W/m2, so the forcing on earth’s energy budget is approximately linear in log(CO2). I’m using log base 2 in this context. So everything else being equal, going from 250 to 500 ppm is the same as going from 500 to 1000 ppm.

The second part that translates radiative forcing into temperature change involves the possible non-linearity of climate feedbacks. This would be especially prevalent if there was a huge “tipping point” in feedback strength. A classic example would be the transition into Snowball Earth. Assume, for example, a complete ice-covered Earth transition occurred as you approach modern day CO2 concentrations divided by 16 (roughly 20-25 ppm). The temperature change is dT. Then dT(CO2/2) ≈ dT(CO2/4) ≈ dT(CO2/8) but there would be a much larger reduction in temperature as you go to CO2/16, since the ice-albedo feedback becomes very large.

For “relatively small changes” around the modern day climate, it probably doesn’t matter too much. That is, dT(CO2 x 2) ≈ dT(CO2 x 4)/2. This isn’t self-evident, but for that linearity to break down, you’d need to find a feedback that had a big impact on the planet’s energy balance and had a bifurcation point centered right near Earth’s modern climate.

I suggest that mechanism (left open in the paper) might be examined pretty thoroughly using a combination of Argo float current data and Windsat wind speed and direction data. http://www.nrl.navy.mil/WindSat/ Windsat data is measuring the effect of wind on the ocean surface, with the wind speed inferred from that. So, it is actually the perfect instrument to gauge momentum transfer to the ocean from the wind in a spatially and temporally resolve manner.

Agreeing with Ray and Chris, if you start at 300 ppm and got to 600 ppm, the change in temperature will be the same as when you start at 500 ppm and get to 1000 ppm. It is the multiplication rather than the starting point that is important.

Chris’ description is also correct but you do need to know something particular about how climate sensitivity is defined. The doubling is instantaneous. The radiation loss is immediately cut by about 4 W/m^2, but this situation cannot continue. The system warms until the top of the atmosphere can radiate at its former rate. Thus, climate sensitivity is defined as a transition from one radiative equilibrium state to another. So, you need to pay attention to your baseline temperature. Taking today’s temperature as the baseline for a doubling to 800 ppm from today’s concentration will not work because the system would not be starting from radiative equilibrium.

I realize I’ve oversimplified. Instantaneously doubling carbon dioxide does not immediately cut outgoing emissions by 4 W/m^2 because water vapor is a fairly large part of that number. Now water vapor is very responsive and is considered a fast feedback but is is tied to temperature which has a delayed response owing mainly to the heat capacity of the oceans, so the water vapor feedback is not at full strength until warming is complete. So, there is really no time when the radiation to space is reduced by 4 W/m^2 even with an instantaneous doubling used in the climate sensitivity formalism.

[Response: Not really. If you could actually double CO2 instantly holding everything else constant, you would have an instant change in OLR of ~4 W/m2. If everything else is allowed to adjust the imbalance comes down quite quickly, but the first year average imbalance would still be around 3 W/m2. – gavin]

Let me read to you from a recently purchased book, “Bioluminsecence” (revised edition, 2012) by O.Shimomura. Page 380 where he discusses Knowledge and it’s application towards understanding a new Bioluminescent mechanism: “Accurate and undistorted knowledge is more important. It will be disastrous if one’s mind is preoccupied with incorrect or distorted preconceptions. The fundamental laws of science and chemistry are absolute and fully trustable. However, various theories, rules and hypotheses made on experiential bases are not laws; these should be trusted only with reservations, especially when studying an unusual phenomena like … ”

Now imagine I have a big red hot brick in my 3rd floor living room. I carry the brick out onto my 3rd floor deck and drop it into my backyard and then run down and carry the brick into the basement. The basement starts warming. The intervening space does not. Thermodynamic incontinence? I can see how your confusion arises. I too detect incontinence but I’m afraid it’s origins are not thermodynamic.

“At the 2 × CO2 equilibrium, the global mean increase
in G, the total greenhouse effect, is around 20 W/m2, sig-
nificantly larger than the 4 W/m2initial forcing and dem-
onstrating the overall affect of the LW feedbacks is positive
(in this model). That is, the extra net absorption by CO2
has been amplified by the response of water vapor and
clouds to the initial forcing. The 20 W/m2
greenhouse effect enhancement is associated with a 15 W/m2 extra emission
from the surface (since the planet has warmed by 2.7°C) and
a 5 W/m2 reduction in outgoing LW that balances a 1.5%
increase in planetary albedo (due to increased cloud cover, a
negative (SW) feedback).” http://pubs.giss.nasa.gov/abs/sc05400j.html

One paper not mentioned by Balmaseda et al. that discusses a mechanism of enhanced interaction between deep water and wind as a result of global warming is Bakun (1990) Science 274 198. In this mechanism, stronger alongshore winds, caused by a higher contrast in pressure between land an ocean owing to early warming of the land, drive surface waters offshore and allow cold deep water to climb the continental shelf and produce stronger upwelling of cold water. http://swfsc.noaa.gov/publications/cr/1990/9003.pdf

Because these upwelling systems are important for ocean ecology, they have been studied in the ecological literature and trends in stronger upwelling have tended to be confirmed there.

It is possible that greater removal of deeper water by the upwellings can help to explain the increased heating of deeper water elsewhere by building a circulation pattern. If so, then some, at least of the wind interaction proposed by Balmaseda et al. (they propose trade wind interactions) could be owing to the effects of warming rather than just independent decadal scale variability in wind behavior. Trade winds have a longer swath over which to work, but alongshore winds have both a warming enhanced heat engine and an underwater slope to help them. And, as Bakun noted, a potential positive feedback in that cold upwellings enhance the pressure contrast already enhanced by warming of the land.

Not sure that’s usefully answerable as asked. Total IR has been given (though not in m/m2, obviously) as a tad over 50% (which surprised me.) However, it’s ‘near infrared’, which means it’s not the same bands Earth radiates. (As you can see in the graph linked below, the sun emits little radiation indeed at wavelengths longer than 4 micrometers, whereas Earth’s radiation is centered at roughly 12 micrometers.)

So, the question is, why do you ask? Knowing that could help make answers relevant.

I wonder, though, do you hold the misconception that only IR warms the surface? All wavelengths absorbed will warm, not just IR. If the total absorbed solar energy value is really what you want, then the EOS site (above) give the June global mean as 187 w/m2. See figure 6.

So as I understand they argue that on shorter time the heat going in to the ocean will not come back? And that the preciding 40 years or so is enough time to get the climate sensitivity for about 50-100 years in to the future… reasonable?

can not say I know how the oceans will react… seams uncertain at least. And a short time frame might be better then a paleo nr for the next 50 years. But how much of ice and say forest changes will it capture? (and how much will addition from tundra etc. contribute to future levels of CO2?)

“The most likely value of equilibrium climate sensitivity based on the energy budget of the most recent decade is 2.0 °C, with a 5–95% confidence interval of 1.2–3.9 °C (dark red, Fig. 1a), compared with the 1970–2009 estimate of 1.9 °C (0.9–5.0 °C; grey, Fig. 1a) …”

and

“The best estimate of TCR based on observations of the most recent decade is 1.3 °C (0.9–2.0 °C; dark red, Fig. 1b). This is lower than estimates derived from data
of the 1990s (1.6 °C (0.9–3.1 °C); yellow, Fig. 1b) or for the 1970–2009 period as a whole (1.4 °C (0.7–2.5 °C); …”

TCR is the transient climate response.

From the figure, the new estimates are not so far away from the old. But I suspect that using only and estimate based on a single decade might be … hasty …

Both the Earth and the Sun emit pretty much as black bodies. For black bodies of the same size, the hotter one emits more at all wavelengths than the cooler one. For black bodies of the same temperature but different sizes, the larger one (more surface area) emits more radiation at all wavelengths. The Sun is both larger and hotter than the Earth so for both reasons it emits more IR radiation than the Earth.